Switch for sewing machine control and thread cutoff

ABSTRACT

A spring-urged lever oscillatably supported from a bag closing sewing machine head and including a free end swingable between first retracted and second extended positions on opposite sides of a feed path along which bags are fed into and discharged from the sewing machine. The lever is spring-biased toward the extended position thereof and its free end includes knife structure for cutting the thread chain extending rearwardly from a bag discharged from the sewing machine as the free end of the lever swings across the feed path of the machine. The base end of the lever has a switch operatively associated therewith for opening the electrical circuit to the electric motor of the sewing machine whenever a bag to be sewn by the machine is not disposed within a predetermined zone extending along the feed path on both sides of the sewing machine head.

United States Patent 1 3,580,197

[72] Inventor Angelo Mascaro 3,053,205 9/1962 Fischbein 112/11 808 S. E. Granger,Des Moines,1owa 3,208,416 9/1965 Davis 112/11 50315 Przmary Exammer--Alfred R. Guest E} 1969 Attorneys-Clarence A. OBrien and Harvey B. Jacobson [45] Patented May 25, 1971 [54] SWITCH FOR SEWING MACHINE CONTROL AND ABSTRAQT: A spring-urged lever oscillat ably stipported from a bag closmg sewing machine head and including a free end THREAD CUTOFF 9 Chums, 4 Drawing Figs swmgable between first retracted and secondextended positions on opposite sides of a feed path along whlch bags are fed [52] U.S.Cl 112/11 into and discharged f the sewing i The lever i Int. Cl Dosh 13/02 spring-biased toward the extended position thereof and its free of Search l 1, e d i lud k ife tr cture for cutting the thread chain ex. tending rearwardly from a bag discharged from the sewing [56] Referencs Cited machine as the free end of the lever swings across the feed UNITED STATES PATENTS path of the machine. The base end of the lever has a switch 2,151,438 3/ 1939 Pierce 1 12/252 operatively associated therewith for opening the electrical cir- 2,569,396 9/1951 Bates 112/252 cult to the electric motor of the sewing machine whenever a 2,630,086 3/1953 Kindseth et al. 112/11 bag to be sewn by the machine is not disposed within a 2,718,201 9/ 1955 Kindseth et 112/11 predetennined zone extending along the feed path on both 3,039,409 6/ 1962 Cordle 1 12/1 1 sides of the sewing machine head.

90 I 24 I l l I I r x, l I t I r--- k l r I l I 20 t l r/13:; 1' I n ""*--i/ 1 l I The sewing machine control switch and bag cutoff assembly of the instant invention has been specifically designed for use in conjunction with a Singer bag closing machine and the mounting plate portion of the instant invention is contoured to form a replacement for the bottom cover plate of the sewing head of the sewing machine whereby the mounting plate may be readily secured to the sewing head in lieu of the cover plate for supporting the mounting plate from the sewing or stitching head.

While the mounting plate portion of the instant invention has been specifically designed for use in conjunction with a Singer bag closing sewing machine, it is to be noted that slightly different contours may be incorporated into the mounting plate portion of the instant invention for adapting the latter for use in conjunction with other types of bag closing sewing machines.

Although some bag closing sewing machines are provided with integral thread cutoffs built into the sewing machine during its manufacture and thread cutting attachments of various designs have been heretofore provided for sewing machines and which are also operative to function as thread cutoffs, these previously known devices have been complex in structure and thus at'least somewhat unreliable in service. Further, while some integral and attachment thread cutoffs have also had electrical control switch means operatively associated therewith for terminating operation of the motor of the associated sewing machine when bags to be closed are not being moved along toward and fed to the sewing machine, some integral and attachment thread cutoffs have not been provided with electrical switch control means for controlling operation of the associated sewing machine motor.

In this regard, when a bag closing sewing machine is not provided with a thread cutoff device and a long line of bags supported on a conveyor are fed through the sewing machine for closing the bags, should one. of the closed bags fall over on its side a chain reaction develops wherein the one bag falling over will pull over all of the other bags which are sewn together. In addition, when a bag closing sewing machine is not provided with automatic motor control means for terminating operation of the electric motor when bags are not being fed through the sewing machine, considerable quantities of thread are wasted and the sewing machine is operated unnecessarily for extended periods of time resulting in excessive wear.

It is accordingly the main object of this invention to provide a combined thread cutoff and motor control accessory for a bag closing sewing machine which will be operative to cut the thread chain from each bag being discharged from the sewing machine and also to terminate operation of the electric motor of the sewing machine when the last bag has been fed through the sewing machine.

Still another object of this invention is to provide a thread cutoff and motor controlling attachment for a bag closing sewing machine which will be operative to cut the thread chain of the last bag sewn closed a spaced distance from the bag.

A final object of this invention to be specifically enumerated herein is to provide a thread cutoff and motor control switch attachment for a bag closing sewing machine which will conform to conventional forms of manufacture, be of simple construction and automatic in operation so as to provide a device that will be economically feasible, long lasting and relatively trouble-free in operation.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIG. 1 is a top plan view of a bag closing sewing machine with a conveyor supported bag being advanced through the sewing machine and the thread cutoff and motor switch control attachment of the instant invention operatively associated with the sewing machine;

Fig. .2 is a top plan view similar to FIG. 1 but illustrating the oscillatable-lever portion of the attachment in an alternate position;

FIG. 3 is a side elevational view of the assemblage illustrated in FIG. I as seen from the right side thereof; and

FIG. 4 is an exploded perspective view of the thread cutoff and motor controlling switch attachment of the instant invention.

Referring now more specifically to the drawings, the nu- I meral generally designates a conventional form of bag cutoff sewing machine including a stitching or sewing head 14 and a backing guide portion 16. An upper housing portion 18 extends between and connects the upper portions of the stitching or sewing head 14 and thebacking guide portion 16. The sewing machine 10 includes a rotary input shaft 20 having a pulley 22 mounted thereon which is driven by an endless flexible belt 24 trained about the pulley 22 and driven by an electric motor power source (not shown) for the sewing machine 10,

The stitching or sewing head 14 includes an inclined undersurface 26 over which a cover plate (not shown) is conventionally secured by means of fasteners 28. However, the attachment of the instant invention, which is generally referred to by the reference numeral 30, includes a mounting plate referred to in general by the reference numeral 32 including a slightly inclined rectangular portion 34 which is apertured as at 36. The portion 34 is of substantially the same general configuration as the aforementioned closure plate and is secured to the undersurface 26 in lieu of the cover plate by means of the fasteners 28 secured through the apertures 36.

The sewing machine 10 is mounted over an elongated conveyor assembly referred to in general by the reference numeral 38 and including an elongated longitudinally shiftable belt reach 40 which moves in the direction of the arrows 42 in FIGS. 1-3 of the drawings. The upper housing portion 18 is centered over and extends transversely of the belt reach 40 whereby the stitching head 14 and backing guide portion 16 are disposed on opposite sides of the longitudinal centerline of the belt reach 40. A plurality of upstanding bags 44 and 46 are disposed on the belt reach 40 at points spaced longitudinally therealong in upright positions and, as may be seen from FIG. 3 of the drawings, the upper marginal edge portions of the bags are disposed at an elevation to be received between the stitching head 14 and the backing guide portion 16 below the upper housing portion 18 as the bags 44 and 46 move along the conveyor assembly 38.

The attachment 30 includes a lever 48 which is apertured at its base endas at 50 and a headed pivot fastener 52 including a smooth shank portion 54 and a diametrically reduced externally threaded shank portion 56 is utilized to oscillatably support the lever 48 from the mounting plate 32 with the smooth shank portion 54 received through the aperture 50 and the threaded shank portion 56 secured through an aperture 58 formed in the mounting plate 32 by means of a washer 60 and nut 62.

The head 64 of the fastener 52 includes a radial bore 66 in which one hooked end 68 of a wire spring 70 is seated. The lever 48 has a notch 72 formed therein bound on one side by means of an upturned flange 74 and on the other side by a downturned flange 76.

A normally open switch 78 is secured to the mounting plate 32 by means of fasteners 80 secured through adjusting slots 82 formed in the mounting plate 32 by means of threaded nuts 84. The switch 78 is received within the notch 72 and the flange portion 76 is engageable with the edge 86 of the mounting plate 32 to limit clockwise rotation of the lever 48 as viewed in FIG. 4 of the drawings while the flange portion 74 of the lever 48 is engageable with the pushbutton actuator 88 of the switch 78 upon counterclockwise rotation of the lever 48 in order to depress the actuator 88 and close the switch 78.

It is to be noted that the switch 78 is serially connected in the electrical circuit (not shown) for the electric motor (not shown) which drives the belt 24 and thus the sewing machine 10. Accordingly, the switch 78, when the lever 48 is oscillated to its clockwisemost limit position illustrated in FIG. 4 of the drawings, terminates actuation of the electric motor and the electric motor is actuated when the lever 48 is swung to its counterclockwise limit position.

The stitching head 14 includes an arcuate shoe 90 which coacts with the backing guide plate 16 to guide the upper marginal portions of the bags 44 and 46 between the stitching head 14 and the backing guide portion 16. In addition, the lever 48 includes a first generally straight carn surface 92 which is first engaged by the bags and a second slightly angulated generally straight cam surface 94 which is engaged by the bags as they move into registry with the shoe 90. Further, the free end of the lever 48 includes an upstanding blade holder 96 from which a razor blade 98 or other sharp blade is supported.

in operation, inasmuch as the plane in which the lever 48 is swingable is disposed below the upper marginal edge portions of the bags 44 and 46 as the latter move through the sewing machine 10, as a bag approaches the sewing machine the leading end of the upper marginal edge portion of the bag 46 engages the surface 92 to partially swing the lever 48 in a counterclockwise direction as viewed from above against the biasing action of the spring 70 which includes a second hooked end 100 engaged with the edge 102 of the notch 72. As the leading edge portion of the bag being advanced toward the shoe 90 nears the latter, the flange portion 74 engages and depresses the actuator 88 so as to close the switch 78 and initiate operation of the sewing machine motor. Then, as the bag moves past the stitching head 14, the upper marginal edge portion of the bag is sewn closed. As the trailing end portion of the upper end of the bag moving through the sewing machine 10 is conveyed out of registry with the free terminal end 104 of the lever 48 disposed beyond the blade 98, the spring 70 snaps the lever 48 in a clockwise direction as viewed from above until the flange portion 76 engages the edge portion 86, during which movement the blade 98 is moved through a vertical plane extending longitudinally of the belt reach 40 and in which the upper marginal edge portions of the bags 44 and 46 are disposed. Accordingly, the blade 98 operates to cut the thread chain 106 which trails from the bag which has just been sewn closed by the sewing machine 10. As soon as the lever 48 swings to its limit of clockwise rotation the flange portion 74 is moved away from theactuator 88 whereby the switch 78 is opened and operation of the sewing machine electric motor is terminated.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

Iclaim:

1. In combination with a bag closing sewing machine of the type including opposing stitching head and base guide plate portions centered above a line conveyor assembly along which upstanding bags are movable, said portions defining an elongated sewing zone therebetween extending along said conveyor assembly including inlet and outlet ends, said portions further defining an entrance throat at said inlet end of said zone facing in upstream direction along the assembly between said portions, a thread cutoff device including a lever pivotally supported from one of said portions for oscillation about an upstanding axis with the other end portion of said lever projecting in a downstream direction along said assembly and swingable between a first extended limit position disposed on the opposite side of said zone and a second retracted limit position disposed on the side of said zone on which said one portion and axis are disposed, upstanding cutting edge means carried by said other end portion of said lever swingable across the centerline of said zone downstream from said portions upon movement of said other end portion from said first position to said second position, means biasing said other end portion toward said extended position, the longitudinal edge of said lever facing said zone when said other end portion is in its retracted position including cam surface means extending across said zone engageable by a bag top entering and moving through said zone for swinging said other end portion from said extended position toward said retracted position and maintaining said other end portion in a retracted position relative to said zone until the bag passing through said zone passes outwardly of the outlet end thereof whereupon said other end of said lever is then free to be biased quickly toward said extended limit position and swing said cutting edge means through said zone to cut the thread chain trailing from the last bag sewn closed by said machine.

2. In combination with a bag closing sewing machine including opposing stitching head and base guide portions defining an elongated sewing zone therebetween extending along a horizontal path on opposite sides of which said portions are disposed, a thread cutoff lever pivotally supported at one end from one of said portions for oscillation about an upstanding axis disposed to one side of said path and swinging movement of said lever between a retracted position extending along said one side of said path and an extended limit position with said lever inclined across said path and the other end thereof disposed on the other side of said path, means yieldingly urging said lever toward said extended position, upstanding cutting edge means supported from said other end of said lever, and the side of said lever adjacent said path when said lever is in said retracted position including cam surface means extending therealong engageable by a bag moving along said path for swinging said lever from said extended position to said retracted position until the trailing edge of the bag passing along said path moves out of registry with the other end of said lever and the latter is freed for swinging toward said extended position for cutting a thread chain trailing from said trailing edge of said bag.

3. The combination of claim 2 wherein said upstanding cutting edge means is spaced along said lever from the terminal end of said other end toward said one end of said lever.

4. The combination of claim 3 including a normally open switch pushbutton-type switch, means supporting said switch from said sewing machine in position for actuation of said switch to close the latter by said lever in response to movement of said lever toward said retracted position, said switch being adapted to be serially connected in an electrical circuit connecting an electric drive motor of said sewing machine to a suitable source of electrical potential.

5. The combination of claim 2 including a mounting plate secured to said stitching head portion, said lever being pivotally supported on said mounting plate, wherein said cutting edge means projects upwardly from the other end portion of said lever.

6. The combination of claim 5 wherein said upstanding cutting edge means is spaced along said lever from the terminal end of said other end toward said one end of said lever.

7. The combination of claim 6 including a normally open switch pushbutton-type switch, means supporting said switch from said sewing machine in position for actuation of said switch to close the latter by said lever in response to movement of said lever toward said retracted position, said switch being adapted to be serially connected in an electrical circuit connecting an electric drive motor of said sewing machine to a suitable source of electrical potential.

8. The combination of claim 7 wherein said switch is also supported from said mounting plate.

9. The combination of claim 8 wherein said one end of said lever includes first and second flange portions engageable with said mounting plate and switch, respectively, for establishing the limit of swinging movement of said lever to said extended position and actuating said switch upon swinging movement of said lever from its extended position toward its retracted position.- 

1. In combination with a bag closing sewing machine of the type including opposing stitching head and base guide plate portions centered above a line conveyor assembly along which upstanding bags are movable, said portions defining an elongated sewing zone therebetween extending along said conveyor assembly including inlet and outlet ends, said portions further defining an entrance throat at said inlet end of said zone facing in upstream direction along the assembly between said portions, a thread cutoff device including a lever pivotally supported from one of said portions for oscillation about an upstanding axis with the other end portion of said lever projecting in a downstream direction along said assembly and swingable between a first extended limit position disposed on the opposite side of said zone and a second retracted limit position disposed on the side of said zone on which said one portion and said axis are disposed, upstanding cutting edge means carried by said other end portion of said lever swingable across the centerline of said zone downstream from said portions upon movement of said other end portion from said first position to said second position, means biasing said other end portion toward said extended position, the longitudinal edge of said lever facing said zone when said other end portion is in its retracted position including cam surface means extending across said zone engageable by a bag top entering and moving through said zone for swinging said other end portion from said extended position toward said retracted position and maintaining said other end portion in a retracted position relative to said zone until the bag passing through said zone passes outwardly of the outlet end thereof whereupon said other end of said lever is then free to be biased quickly toward said extended limit position and swing said cutting edge means through said zone to cut the thread chain trailing from the last bag sewn closed by said machine.
 2. In combination with a bag closing sewing machine including opposing stitching head and base guide portions defining an elongated sewing zone therebetween extending along a horizontal path on opposite sides of which said portions are disposed, a thread cutoff lever pivotally supported at one end from one of said portions for oscillation about an upstanding axis disposed to one side of said path and swinging movement of said lever between a retracted position extending along said one side of said path and an extended limit position with said lever inclined across said path and the other end thereof disposed on the other side of said path, means yieldingly urging said lever toward said extended position, upstanding cutting edge means supported from said other end of said lever, and the side of said lever adjacent said path when said lever is in said retracted position including cam surface means extending therealong engageable by a bag moving along said path for swinging said lever from said extended position to said retracted position until the trailing edge of the bag passing along said path moves out of registry with the other end of said lever and the latter is freed for swinging toward said extended position for cUtting a thread chain trailing from said trailing edge of said bag.
 3. The combination of claim 2 wherein said upstanding cutting edge means is spaced along said lever from the terminal end of said other end toward said one end of said lever.
 4. The combination of claim 3 including a normally open switch pushbutton-type switch, means supporting said switch from said sewing machine in position for actuation of said switch to close the latter by said lever in response to movement of said lever toward said retracted position, said switch being adapted to be serially connected in an electrical circuit connecting an electric drive motor of said sewing machine to a suitable source of electrical potential.
 5. The combination of claim 2 including a mounting plate secured to said stitching head portion, said lever being pivotally supported on said mounting plate, wherein said cutting edge means projects upwardly from the other end portion of said lever.
 6. The combination of claim 5 wherein said upstanding cutting edge means is spaced along said lever from the terminal end of said other end toward said one end of said lever.
 7. The combination of claim 6 including a normally open switch pushbutton-type switch, means supporting said switch from said sewing machine in position for actuation of said switch to close the latter by said lever in response to movement of said lever toward said retracted position, said switch being adapted to be serially connected in an electrical circuit connecting an electric drive motor of said sewing machine to a suitable source of electrical potential.
 8. The combination of claim 7 wherein said switch is also supported from said mounting plate.
 9. The combination of claim 8 wherein said one end of said lever includes first and second flange portions engageable with said mounting plate and switch, respectively, for establishing the limit of swinging movement of said lever to said extended position and actuating said switch upon swinging movement of said lever from its extended position toward its retracted position. 